Stable and uniform multiwavelength erbium-doped fiber laser based on a microfiber knot resonator with a Sagnac loop reflector

In this paper, we proposed and demonstrated a stable and uniform multiwavelength erbium-doped fiber laser (EDFL) by using of the filer action of microfiber knot resonator (MKR) with a Sagnac loop reflector. By embedding the resonator to the ring cavity of the EDFL by means of a circulator, a multiwavelength EDFL is created. The number of the lasing lines with different wavelengths within 3-dB bandwidth is up to 42, the linewidth of each lasing line is about 0.05 nm and the side-mode suppression ratio is about 45 dB. The results demonstrate that the MKR with a Sagnac loop reflector can be employed as a high performance comb filter to realize a stable and uniform multiwavelength fiber laser. © 2017, The Optical Society of India.